As our environment and social mores increasingly play a major role in the incidence of upper and lower respiratory tract carcinogenesis, the need to comprehend etiopathogenesis and control of these cancers increases proportionately. This proposal directs its attention to improving our knowledge of the persistent immunosuppressed status of patients with carcinoma of the head and neck. Our laboratory has reported that these patients have excessive levels of circulating soluble immune complexes (SIC) in their sera. We have evidence to suggest these SIC may be in part responsible for such immunosuppression. Our approach is to isolate, purify and characterize the constituents of the SIC. Also, the biological role of SIC or its components in causing active immunosuppression will be studied using in vitro immunologic techniques which assess cellular immune potential. The data we obtain should clarify the role of SIC in the pathogenesis of carcinoma of the head and neck. Finally, our results should set the stage for possible new and unique modes of treatment of head and neck cancer.